Electric heater.



G. D. HASKINS.

ELECTRIC HEATER. APPLIOATIOK nun JUNE 23, 1909.

963,892. Patented July 2, 1910 Fi .l.

Fig.2.

Wifmesses: inventor w Caryl DHasK'ms,

unrrnn STATES PATENT OFFICE.

CARYL D. HASKINS, F SCHENECTADY, YORK, ASSIGNOR T0 GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

I ELECTRIC HEATER.

Specification of Letters Patent. Patented Jul 12 1910.

Application filed June 23, 1909. Serial No."503,814.

To all whom it may concern:

Be it known that I, (hurt. D. HASKINS, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in ElectricHeaters, of which the following is a specifi cation.

' This invention relates to electric heaters and has for its object theprovision of a device of this character in which the joint between theactive heating element and the vessel or other device to be heated ismade so as to produce an intimate thermal relationship between the partsand thereby increase the etlicioncy of the heater as a whole.

One of the greatest difiiculties encountered in the construction ofelectric heating devices is the production of an efficient contactbetween the active heating element and the utensil or body to be heated.Moreover. the most desirable type of heater for ordinary service is onein which the utensil is not directly attached to the electric circuit:that is, one in which the utensil is heated on an electrically heatedstove. In this form of heating apparatus, the contact between theheating element and the utensil is at its worst.

One of the objects of my invention is to improve the contact between theutensil and the. heating element.

in carrying out my invention, I embody in a heater a material which issoftened or rendered plastic or even fluid by the heat developed in theheater. By softening the material, a very intimate thermal relation isproduced between the softened material and the heating element. I havefound that byhaving the heating surface of the fusible material soarranged that the utensil to be heated rests upon and sinks into it, avery efiicient heating joint is produced. I have also found that bycovering the material with a shield or screen the softened material iskept from spilling.

In the accompanying drawing, in which I have shown my invention embodiedin concrete form for the purpose of illustration, Figure 1 represents aside elevation, partly in section, of the heater, and Fig. 2 re n-esentsa similar view with a cooking utensil in place on the heater.

'. Referring to the drawing, 10 represents a heating element which isarranged in the form of a flat ring, with a fusible material 11 inintimate thermal relation therewith. The particular arrangement of theheating element and its specific relation to the fusible material formsno part of my invention, but for the purpose of illustration I haveshown a unit of the type described and claimed in the application filedby Logan and Faccioli on November 27, 1908, Serial No. 464,517. In thisform of unit there is provided an insulating base 12 preferably circularin form to which the heating unit is secured by means of bolts 13. Inthe form in which I have shown the unit, the resistance conductor 10 iswound spirally around a ring ll of insulating material, such, forinstance, as mica, and the terminals brought out at the pins 15. Thisring with the conductor wound upon it is then clamped between two sheetsof mica 16 and inclosed in a sheet metal casing and the whole secured tothe base 12 by the bolts 13. The upper surface .of the unit is thencovered with the fusible metal 11. This is held in place by the metallicrim 1? which is permanently secured to and forms part of-the heater bybeing bent around the heating element as shown. This rim forms a well ordish for containing the fusible metal. The particular material which isvused for this purpose forms no part of my invention and may be varied asde-' sired, depending upon the temperature at which it is desired thatthe material shall soften. I have found, for instance, that an alloy oftin, cadmium and bismuth can be formed, which will become soft orplastic at 110 C. and will be quite fluid at 125 C. This alloy,moreover, does not show surface oxidation after heating. In order toprevent the material which has softened from spilling, I provide ashield 18 wh1ch normally covers the metal, as shown inFig. l, and whichis adapted to be forced down into the metal when the utensil 19 restsupon it. This shield may be a fine metal gauze or may be constructed inany suitable manner. It will be observed that when current 1s passedthrough the heating unit and the a head around the bottom edge of the receptacle by the metal rising around it. This produces a very efiicientjoint between the heating unit and the utensil, fillin all gaps due towarping or other causes. en the receptacle is removed, the shield whichhas been forced down with the utensil, as shown, will return to itsoriginal position and the fusible metal will harden when the current isturned off.

. I have shown my invention for the purposes of illustration as embodiedin a stove having a fiat heating surface and the utensil arranged toengage the same, but it should be understood that I do not limit myinvention thereto. It is obvious that the heating apparatus may be ofany desired form and arranged to accommodate any other device or body tobe heated, instead of a cooking utensil, the underlying idea being theproduction of a heating device in which the joint between the activeheatin element and the body to be heated is in a p astic or fluid form.Various modifications of my .inven- -;tion will, therefore, suggestthemselves to those skilled in the art, without departing from thespirit of my invention, the scope of which is set forth in the annexedclaims.

Having now fully described my invention, what I claim as new and desireto secu ie'by Letters Patent of the United States is 1: An electricheater having a heating surface which is softened by the heat developedin said heater.

2. An electric heater having a heating surface which is rendered plasticby the heat developed in said heater.

3. 'Anelectric heater having a material in thermal relation with theheating element face composed of a materia which is softened by the heatdeveloped in said heater and a body to be heated arranged to sink intosaid softened material.

6. An electric heater having a heating surface which is softened by theheat developed in said heater and a shield normally coveringsaid surfaceand arranged to sink intothe softened surface.

7. An electric heater having a heating surface composed of a materialwhich is softened by the heat developed in said heater, a shieldnormally covering said surface and a vessel to be heated arranged toengage said shield and sink into the softened material.

8. An electric heater comprising .a flat heating unit having itseffective heating surface covered with a material which is renderedfluid by the heat developed in said heater, a shield normally coveringsaid material and a vessel to be heated arranged to engage said heaterand sink into the softened material.

In witness whereof, I have hereunto set my hand this 22nd day of June,1909.

CARYL D. HASKINS.

Witnesses:

BENJAMIN B. HULL, .HELEN ORFORD.

which is softened by the heat developed in l said element.

